With the increase in display panel size for liquid crystal display devices in these years, there is a demand for a reduction in the non-display area including a bonded portion at which the substrates are bonded to each other with an adhesive or the like. For this purpose, the device design tends to narrow the spacing between the substrate peripheral edge and the display area edge (hereinafter will be referred to as “frame-narrowing”.)
FIG. 5 is a schematic plan view of the display panel of a conventional liquid crystal display device of frame-narrowing design, showing the configuration of wiring formed on a transparent substrate in the display panel. As shown in FIG. 5, the display panel of the liquid crystal device has an arrangement including wiring 4 formed of a conductive metal film, a substrate (hereinafter will be referred to as liquid crystal driving substrate) 1 formed on its internal surface with switching devices (not shown) each comprising a thin film transistor (TFT) for example, and a liquid crystal material layer 6 interposed between the liquid crystal driving substrate 1 and a counter substrate (not shown) facing the liquid crystal driving substrate 1. The liquid crystal driving substrate 1 and the counter substrate have their respective peripheral portions bonded to each other with an adhesive layer 5 except a region as a liquid crystal material injecting portion 2. The liquid crystal material layer 6 is formed by injecting a liquid crystal material into the space defined between the two substrates fixed to each other with the adhesive layer 5. Thereafter, an ultraviolet curing sealant 3 is applied to the liquid crystal material injecting portion 2 and then cured by irradiation with ultraviolet rays from the principal plane side of the display panel. Thus, the liquid crystal material injecting portion 2 is sealed.
In such a display panel the peripheral region in which the adhesive layer 5 is included and the wiring 4 positioned is an area (non-display area) c that does not participate in the display. A display area b is located as surrounded by the non-display area c. In a liquid crystal display device of frame-narrowing design, the non-display area c is reduced to enlarge the display area b. For this purpose, the wiring 4 is positioned on the side close to the peripheral edge of the display panel, and the interface a between the liquid crystal material layer 6 and the sealant 3 (hereinafter will be referred to as “liquid crystal-sealant interface a”) is positioned also on the side close to the peripheral edge of the display panel. Though not shown here, the display area b comprises a plurality of pixels arranged in matrix and has a network of wiring associated with the pixels. For example, the wiring 4 serves as the so-called rescue wiring to be used when a break occurs in the network of wiring extending in the display area b.
In the aforementioned conventional liquid crystal display device of frame-narrowing design, ultraviolet rays for curing the sealant 3 may be blocked by the wiring 4 in the case where the sealant 3 has reached up to a region in which the wiring 4 is positioned due to materials, equipment or the like used in the manufacturing process. Particularly in a case where the wiring 4 is positioned at a location corresponding to the liquid crystal-sealant interface a at which the liquid crystal material layer 6 and the sealant 3 are in contact with each other, the wiring 4 formed of a metal material, which does not transmit ultraviolet rays, blocks ultraviolet rays for irradiation. For this reason, the sealant 3 in an uncured state is brought into contact with the liquid crystal material layer 6. Therefore, the liquid crystal material layer 6 is contaminated, which results in problems with the display device including the occurrence of defective image display, lowered yield and degraded quality in reliability and the like.